TGFB1 and neoplasm: To determine if the blockade of TGF-β, at a time point after anti-tumor CTLs have been induced, enhances secondary tumor growth, we administered sTGF-βR (TGF-β-blockade) or IgG2a (control) to BALB/c mice after AB12 tumors had formed but before re-challenge with a second AB12 “metastatic focus” in the opposite flank.